sturdiness vs sturdy

sturdiness is a noun but sturdy is not a noun.

Word	Noun	Adjective	Verb	Adverb
sturdiness	Yes	No	No	No
sturdy	No	Yes	No	No

sturdiness (noun)	sturdy (noun)
the property of something that is strongly built
resoluteness evidenced by strength of character
the state of being vigorous and robust

sturdiness (adjective)	sturdy (adjective)
	not making concessions
	having rugged physical strength; inured to fatigue or hardships
	substantially made or constructed